Lessons from Toxicology: Developing a 21st-Century Paradigm for Medical Research.

Biomedical developments in the 21st century provide an unprecedented opportunity to gain a dynamic systems-level and human-specific understanding of the causes and pathophysiologies of disease. This understanding is a vital need, in view of continuing failures in health research, drug discovery, and clinical translation. The full potential of advanced approaches may not be achieved within a 20th-century conceptual framework dominated by animal models. Novel technologies are being integrated into environmental health research and are also applicable to disease research, but these advances need a new medical research and drug discovery paradigm to gain maximal benefits. We suggest a new conceptual framework that repurposes the 21st-century transition underway in toxicology. Human disease should be conceived as resulting from integrated extrinsic and intrinsic causes, with research focused on modern human-specific models to understand disease pathways at multiple biological levels that are analogous to adverse outcome pathways in toxicology. Systems biology tools should be used to integrate and interpret data about disease causation and pathophysiology. Such an approach promises progress in overcoming the current roadblocks to understanding human disease and successful drug discovery and translation. A discourse should begin now to identify and consider the many challenges and questions that need to be solved.

A vision becoming reality.

Non-animal science in toxicology and health research has been progressing for decades, but only now is it being seen widely as advanced science. The emergence of novel human biology-based tools and models, combined with legislative and regulatory change, a 21st century concept for toxicology, continuing failures in the drug pipeline, and systematic critiques of animal models, have created a pivotal moment of change. The leading edge is starting to become the norm. Humans and other animals are likely to benefit as a result.

Estimates for worldwide laboratory animal use in 2005.

Animal experimentation continues to generate public and political concern worldwide. Relatively few countries collate and publish animal use statistics, yet this is a first and essential step toward public accountability and an informed debate, as well as being important for effective policy-making and regulation. The implementation of the Three Rs (replacement, reduction and refinement of animal experiments) should be expected to result in a decline in animal use, but without regular, accurate statistics, this cannot be monitored. Recent estimates of worldwide annual laboratory animal use are imprecise and unsubstantiated, ranging from 28-100 million. We collated data for 37 countries that publish national statistics, and standardised these against the definitions of 'animals', 'purposes' and 'experiments' used in European Union Directive 86/609/EEC. We developed and applied a statistical model, based on publication rates, for a further 142 countries. This yielded our most conservative estimate of global animal use: 58.3 million animals in 179 countries. However, this figure excludes several uses and forms of animals that are included in the statistics of some countries. With the data available, albeit for only a few countries, we also produced, by extrapolation, a more comprehensive global estimate that includes animals killed for the provision of tissues, animals used to maintain genetically-modified strains, and animals bred for laboratory use but killed as surplus to requirements. For a number of reasons that are explained, this more-comprehensive figure of 115.3 million animals is still likely to be an underestimate.

Replacing animal experiments: choices, chances and challenges.

Replacing animal procedures with methods such as cells and tissues in vitro, volunteer studies, physicochemical techniques and computer modelling, is driven by legislative, scientific and moral imperatives. Non-animal approaches are now considered as advanced methods that can overcome many of the limitations of animal experiments. In testing medicines and chemicals, in vitro assays have spared hundreds of thousands of animals. In contrast, academic animal use continues to rise and the concept of replacement seems less well accepted in university research. Even so, some animal procedures have been replaced in neurological, reproductive and dentistry research and progress is being made in fields such as respiratory illnesses, pain and sepsis. Systematic reviews of the transferability of animal data to the clinical setting may encourage a fresh look for novel non-animal methods and, as mainstream funding becomes available, more advances in replacement are expected.

Report of a meeting to discuss a National Centre for the Replacement of Animals in Experiments.

Following the publication of their joint proposal for a National Centre for the Replacement of Animals in Experiments in 2002, the Dr Hadwen Trust and the Lord Dowding Fund organised a meeting, held on 18 November 2003 at Portcullis House, Westminster, in London, in order to discuss the concept further. A one-page summary of their proposal is attached as an appendix, and full copies are available from the Lord Dowding Fund and the Dr Hadwen Trust. The meeting aimed to discuss the need to stimulate and promote research to replace animal experiments by means of a National Centre (a coordinating body), and how this should be established and funded. Participants, numbering about 80 in total, included politicians (national and European), government officials, scientists, funding bodies and animal welfare representatives. This report is a summary of the issues raised by speakers and other participants at the meeting.